Mercury Tilt Switch
Mercury tilt switches consist of one or more sets of electrical contacts in a sealed glass bulb which contains a bead of mercury. Gravity constantly pulls the drop of mercury to the lowest point in the bulb. Mercury has excellent electrical conduciveness. When the switch is tilted in the appropriate direction, the mercury touches the set of contacts, completing the electrical circuit through the set of contacts. Tilting the switch in the opposite direction causes the mercury to move away from the set of contacts, breaking the circuit.
Tilt switches are typically found in thermostats, float switches, boiler pressure controls, motion sensors and other devices.
